LOCAL INTERFACE COMPOSITION AND EXTENDED DEFECT DENSITY IN ZNSE GAAS(001) AND ZNSE/IN0.04GA0.96AS(001) HETEROJUNCTIONS/

We have recently shown that in II-VI/III-V heterojunctions and related devices fabricated by molecular beam epitaxy, the II/VI flux ratio em ployed during the early stages of II-VI growth can be used to control the local interface composition and the band alignment. Here we demons trate that the local interface composition in pseudomorphic, strained ZnSe/GaAs(001) heterostructures as well as lattice-matched ZnSe/In0.04 Ga0.96As(001) heterostructures also have a dramatic effect on the nucl eation of native stacking fault defects. Such extended defects have be en associated with the early degradation of blue-green lasers. We foun d, in particular, that Se-rich interfaces consistently exhibited a den sity of Shockley stacking fault pairs below our detection limit and th ree to four orders of magnitude lower than those encountered at interf aces fabricated in Zn-rich conditions. (C) 1997 American Vacuum Societ y. [S0734-211X(97)09104-X].